Dimethylformamide → Ethyl 2,5-dichloronicotinate

Participants

Reaction Steps

5-Chloro-2-hydroxynicotinic acid [11.95 g; Synthetic Comm. (1989), 19, 553] was suspended in thionyl chloride (52 mL) and anhydrous dimethylformamide (2 mL) was added. The suspension was refluxed 3 h, then concentrated under a nitrogen stream to remove the bulk of excess thionyl chloride before adding anhydrous ethanol (30 mL) giving a mixture of the desired ester and diethyl sulfite. The resulting mixture was concentrated in vacuo to remove the ethanol yielding a suspension. The solids were then filtered off and washed with anhydrous diethyl ether (2×10 mL). The combined filtrates were concentrated in vacuo yielding crude product. Purification by silica gel chromatography (ethyl acetate:hexanes 8:92) gave pure title compound (4.75 g).

Provenance & Evidence